Bulbs being dug up by naughty animals

I have recently planted up some globemaster and drum stick alliums in a large pot and am looking forward to seeing them come up in the spring. The only problem is that on several occasions recently I have found dug holes in the soil and allium bulbs exposed/taken!! I am thinking of getting some netting at the weekend and placing it over the pot along with the newly planted garlic bulbs (as these may be next).

My wife saw a fox out in the car park the other night and I know there are squirrels knocking about bur I cannot say for sure what is digging them up? Any ideas?

Its really annoying, last year I had slugs eat many alliums in the spring and this year they are being messed with only weeks after planting!! They are destined for failure